Magnetic resonance imaging (MRI) is a medical imaging technique used to visualize detailed internal structures. MRI makes use of the property of Nuclear magnetic resonance (NMR) to image nuclei of atoms inside the body.
An MRI machine uses a powerful magnetic field to align the magnetization of some atoms in the body, and radio frequency fields to systematically alter the alignment of this magnetization. This causes the nuclei to produce a rotating magnetic field detectable by a scanner and this information is recorded to construct an image of the scanned area of the body. Strong magnetic field gradients cause nuclei at different locations to rotate at different speeds. 3-D spatial information can be obtained by providing gradients in each direction. The nuclei absorb the external radio frequency (RF) in the transmit phase and a RF signal of its own receive phase. This signal is captured with the antenna. The signal is then amplified and processed to create an image.
MRI provides good contrast between the different soft and hard tissues of the body, it is especially useful in imaging the brain, muscles, the heart, and cancers compared to other medical imaging techniques such as computed tomography (CT) or X-rays. Unlike CT scans or traditional X-rays, MRI uses no ionizing radiation. Thus, it is possible to image and diagnose people of any age with MRI. Due to its flexibility and sensitivity to a broad range of tissue properties, MRI has recently been in the forefront of research and development, especially in pediatric imaging.
Most pediatric magnetic resonance imaging applications currently use adult RF coils to produce images of children and people of smaller proportions. It is believed that the use of full size coils on a child or patient of smaller proportions reduces the quality of pediatric images. Full size coils have a large field of view (FOV) spanned by their physical dimensions. Consequently, the use of adult coils over smaller anatomies often reduces signal to noise ratio (SNR) and imaging resolution, resulting in sub-optimal image quality.
What is needed, therefore, is a device or system which can produce high resolution and high SNR in the images of infants and smaller patients with smaller proportions.